Solving Harmonics ?

[Holly Tucker]

Mike, I read your article about harmonics, what kind of devices generate them and how many in the electrical industry are unaware of the damage from harmonics.

I wonder if you're familiar with a device (I believe new on the market) that removes harmonics, targeted towards high use customers, made by a company called LineLoss Pro. They are claiming energy savings and equipment protection from the use of their device.

Could you tell me your thoughts on this device as it would appear to be quite useful?

Besides promised energy savings from the device, the company touts the device helps save equipment damage from harmonics. Is such damage a real issue?

Holly

 

[jumper]

I notice you are in sales, is this your product?
Advertising is forbidden.

 

[Sierrasparky]

Damage of Electrical equipment can be a problem.
I have seen failed switchgear , burned neutrals, burned breakers. Can I prove beyond doubt it was the harmonics. probably not. Just my experience.

 

[gar]

160202-0050 EST

Holly Tucker:

Any non-linear device will generate harmonics from a pure sine wave. Any non-sine wave already contains harmonics.

A non-sine wave applied to a non-linear device will create modified and new harmonics.

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[gar]

160202-0057 EST

LineLoss Pro is probably a fraud for the most part. Hyper advertizing and no technical details. It may simply be a low pass filter. On the surface it is like the advertizing for power factor correction devices that can not and do not produce the savings claimed.

A first test to run is to measure the power input to an unloaded cheap induction motor with and without the so called power saver. This is a load with with a low power factor. This must be done under constant voltage input to the test setup. There is some harmonic content to this load. When loaded the power factor will be better and relatively speaking there is less harmonic content.

A load with a high harmonic content in its input current is an older computer switching power supply or any power supply using a capacitor input filter. Do a similar test on such a supply.

A high quality power meter must be used in these tests.

..

 

[junkhound]

Have seen lots of harmonic damage.

However, adding an inductor in the neutral of a wye load does nothing except reduce harmonic currents in the neutral* and unbalance the loads. *at least keeps the white wire from turning brown, eh?

What jumper said, cheap shot at an add for a hokey 'product', to use the word product loosely.

PS: what gar said also, fraud.

 

[iwire]

Have seen lots of harmonic damage.

I am all ears because most of the time folks saying that are paid for by the copper industry.

 

[ptonsparky]

The only time I have seen a white wire turn brown is at the termination and most of those were from poor termination or an outright overload due to improperly shared neutrals.

Could very well be from my limited exposure to the problem though.

 

[junkhound]

re: ....am all ears.....


Best harmonic problem I recall was a 480-120 delta-wye transformer on a relatively new 8 story office building.

Built in 1986. Initially only a few centralized PCs. In early 1990's in February, all employees were provided with a new PC and monitor.

A month or so later, on the first really warm day, there was a power outage. One of the 480-120 delta-wye transformers on the roof released it's magic smoke.

All of the hundreds of new PCs had simple full wave bridge capacitor input power supplies, no PFC circuits that most have now.

The triplett harmonics generated by the PCs all circulated in the delta primaries (tripletts short circuited since they are all in phase) and burnt out the transformer. All the delta wyes were replaced with increased KVA ratings to be able to dissipate the short circuit harmonic currents in the delta primary.

 

[Besoeker]

Have seen lots of harmonic damage.

However, adding an inductor in the neutral of a wye load does nothing except reduce harmonic currents in the neutral* and unbalance the loads. *at least keeps the white wire from turning brown, eh?

What jumper said, cheap shot at an add for a hokey 'product', to use the word product loosely.

PS: what gar said also, fraud.

Ummm.........

Reduction in daily kilowatt hour (kwhr) consumption ranges from 5-32%

Snake oil anyone??

 

[Jraef]

Here we go again. It's been a while since a new scam has been foisted, but I suppose there is no end to the guillability of the public at large.

Sorry, not going to fly around the professionals in here. We've been down this road several times and it always goes to the same place: Very sketchy technical details, but lots of "testimonial" evidence given by poor saps who were duped into buying it, so will believe strongly in the misinterpretation of evidence to support their error and vehimitly defend their decision.

It's a line reactor, it even says "inductive low pass filter" in one of the several different names used in articles for the same thing.

By the way, a dead giveaway as to it being a scam is that there is only a website and a toll free number available for the company, no physical address. That helps them avoid lawsuits in states with better consumer protection laws. Also, as I mentioned, there are at least 3 different company names selling this same device, many of which link back to each other. Another classic scam tactic.

Run away...

 

[iceworm]

Have seen lots of harmonic damage. ....

I am all ears because most of the time folks saying that are paid for by the copper industry.

...Best harmonic problem I recall was a 480-120 delta-wye transformer on a relatively new 8 story office building.

Built in 1986. Initially only a few centralized PCs. In early 1990's in February, all employees were provided with a new PC and monitor.

A month or so later, on the first really warm day, there was a power outage. One of the 480-120 delta-wye transformers on the roof released it's magic smoke.

All of the hundreds of new PCs had simple full wave bridge capacitor input power supplies, no PFC circuits that most have now.

The triplett harmonics generated by the PCs all circulated in the delta primaries (tripletts short circuited since they are all in phase) and burnt out the transformer. All the delta wyes were replaced with increased KVA ratings to be able to dissipate the short circuit harmonic currents in the delta primary.

I'm not saying you are wrong, but I am curious on how you know this.

First, I've got some question if any desktop computers ever had linear PS. But that likely doesn't matter, switching power supplies put out out a lot of harmonics.

Second, are these triplett harmonics generated by the PCs something you actually measured? Yes, I understand you could not have measured them on the dead transformer. However did you go back and measure the currents/harmonics on the new transformer? Did you verify this high primary current/high secondary neutral current was caused by the added PCs?

I got to get to work - later

ice

 

[Besoeker]

One of the most frequent harmonics failures I have come across have been naked PFC capacitors. They are a natural sink for harmonics. In my designs we used detuning reactors in series with them. Three phase industrial applications so generally the lowest order was fifth so the tuning frequency was set below that.

 

[Holly Tucker]

Harmonics as Mike Sees It

Harmonics as Mike Sees It

Thanks for the replies regarding my question about a device for capturing harmonics.

I'm not an electrician. I am considering a sales job with a company that makes such a device and am doing my due diligence by asking "experts." I would never have posted in this forum were it not for the fact Mike Holt said in an article he wrote:

Harmonic currents and voltage distortion are becoming the most severe and complex electrical challenge for the electrical industry. The problems associated with nonlinear loads were once limited to isolated devices and computer rooms, but now the problem can appear throughout the building and utility system....The effects of harmonic currents on electrical distribution systems are not understood by most in the electrical industry.

Scam or not, sounds like there's room for knowledge sharing within your industry.

Blessings,
Holly

 

[junkhound]

edit PS: Holly, thanks for the clarification - IMhO, you may be better off finding a better product to represent ?

I'm not saying you are wrong, but I am curious on how you know this.

First, I've got some question if any desktop computers ever had linear PS. But that likely doesn't matter, switching power supplies put out out a lot of harmonics.

Second, are these triplett harmonics generated by the PCs something you actually measured? Yes, I understand you could not have measured them on the dead transformer. However did you go back and measure the currents/harmonics on the new transformer? Did you verify this high primary current/high secondary neutral current was caused by the added PCs?

I got to get to work - later

ice

Agree, the power supplies did NOT have linear supplies, but the input to the switchers that put out +/-12V and +/-5 V for the PCs were the simple diode bridge with capacitor (similar to insert). If you look at the current of a modern 19V Dell laptop power supply, it is near unity PF with close to zero harmonics, but those have a boost PFC circuit ahead of the switchers. Note: that also makes it easy to pug into either 85 V or 260V ac, as the voltage feeding the switchers is typically boosted to 400 V.

The office building details were verbal inputs from a facilities engineer, I never saw those specific measurements. Had dealt with the situation outlined below in the same time frame, we were basically 'comparing notes' on the problem similarities.

The inserts below are a couple of slides presented to managers showing typical harmonic problems, a real problem from 25 years ago, now everything non-linear (power supplies, motor drives, etc) is required to have PFC (power factor correction) boost circuits if attached to the 400 Hz distribution. There was LOTs of data taken for this problem (as at 2 AM so as to not interfere with assembly line) and was well documented. The waveforms are tracings of actual test data, which I do not have access to any longer. The voltages and currents are the actual measured values for this particular case.


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[sparkyrick]

I know how to solve harmonics. Abandon AC completely and switch the entire world to DC. Maybe Edison was right afterall!

 

[don_resqcapt19]

Thanks for the replies regarding my question about a device for capturing harmonics.

I'm not an electrician. I am considering a sales job with a company that makes such a device and am doing my due diligence by asking "experts." I would never have posted in this forum were it not for the fact Mike Holt said in an article he wrote:

Harmonic currents and voltage distortion are becoming the most severe and complex electrical challenge for the electrical industry. The problems associated with nonlinear loads were once limited to isolated devices and computer rooms, but now the problem can appear throughout the building and utility system....The effects of harmonic currents on electrical distribution systems are not understood by most in the electrical industry.

Scam or not, sounds like there's room for knowledge sharing within your industry.

Blessings,
Holly

Holly,
Solving potential issues caused by harmonics is far different from saying solving those "problems" will save over 12% of your electrical energy costs.

As far as the "harmonic problem" the vast majority of the information out there that tells you there are harmonic problems comes from a source that wants to sell you something to solve that "problem".

 

[kaichosan]

The only savings I know is not being penalize by POCO for a high THD. I did harmonic a analysis and test on a number of Water Treatmsnt plants to make sure of their THD system contribution was within acceptability. Majority of the motors were VFDs.

Sent from my SM-G900P using Tapatalk

 

[iwire]

re: ....am all ears.....


Best harmonic problem I recall was a 480-120 delta-wye transformer on a relatively new 8 story office building.

Built in 1986. Initially only a few centralized PCs. In early 1990's in February, all employees were provided with a new PC and monitor.

A month or so later, on the first really warm day, there was a power outage. One of the 480-120 delta-wye transformers on the roof released it's magic smoke.

All of the hundreds of new PCs had simple full wave bridge capacitor input power supplies, no PFC circuits that most have now.

The triplett harmonics generated by the PCs all circulated in the delta primaries (tripletts short circuited since they are all in phase) and burnt out the transformer. All the delta wyes were replaced with increased KVA ratings to be able to dissipate the short circuit harmonic currents in the delta primary.

The first question I have is a simple one.

Did the buildings electrical system keep up with the general requirements of article 220 or did the load simply grow and grow?

 

[gar]

160203-2139 EST

Some plots from the input current for a late1990s IBM PC:

The current waveform is noisy because of the low current and the use of a clamp Hall device current sensor. The probe full scale is 20 A = 2 V. The power system source voltage waveform distortion at the peak is not from this one computer, but from the 100s of thousands on the electric grid.

In the FFT plot you see the fundamental, and odd harmonics thru the 13th. The solid vertical cursor is at 300 Hz, the dashed vertical cursor is at the 13th, 780 Hz.
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